Methicillin resistance in either pathogenic or normal floral staphylococci became one of the nuisances that most annoying clinicians in the field of infectious disease. In order to establish effective therapeutic regimens for infections caused by
methicillin-resistant(MR) staphylococci, which become one of the most troublesome nosocomial microorganisms, this study was carried out. Antimicrobial susceptibility of 28 strains of MR Staphylococcus aureus(SA), 10 strains of MR S.
epidermidis(SE), and
13 strains of MR S. saprophyticus(SS) isolated from various clinical specimens to 19 antimicrobial agents was evaluated by agar dilution method. Nineteen agents tested were as follow:7 cephalosporins of all generations, 4 aminoglycosides,
erythromycin,
fosfomycin. pefloxacin, norfloxacin, doxycycline, vancomycin, and fusidate. Among those agents, norfloxacin, vancomycin, and fusidate showed excellent antistaphylococcal activity with resistance less than 20%, and most of the strains showed
resistance
were MRSS. Doxycycline, cefamandole, pefloxacin, rifampin, and cefazolin showed relatively good antimicrobial activity, while other agents were hardly effective. Cefamadole(CMDL) is well known to have superior antistaphylococcal activity
especially
in
vivo to other cephalosporins. Combincd effect of CMDL with doxycycline(DXTC), fusidate (FA), norfloxacin(NFLX), and rifampin(RFP) was evaluated by checkerboard dilution method. CMDL-FA combination showed best result with 72.6% of synergy, 23.5%
of
additivity and only 3.9% of antagonism. CMDL-RFP combination resulted in 54.9% of synergy, 41.2% of additivity, and 3.9% of antagonism. CMDL-DXTC combination resulted in 11.8% of synergy, 74.5% of additivity, and 13.7% of antagonism. CMDL-NFLX
combination resulted in 3.9% of synergy, 76.5% of additivity, and 19.6% of antagonism.
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